Let's Make Robots!

LIDAR, LRF, etc HELP!

So I love lasers. Really, really love them. I've bought about a dozen different types of laser modules (green/red) to play with on my next bot. However I'm at a loss as to where to even begin on using them as more than just a "frickin laser beam", and have it actually DO SOMETHING!

I've been scouring the net and LMR for info on building a cheap Laser Rangefinder and/or LIDAR system, I love the idea of mapping a room with lasers and having the information sent back to the microprocessor and/or base station pc for visual processing by the user. However, I'm also confused about these two terms; are they the same thing?

I've seen Fritzl's post (http://letsmakerobots.com/node/1833) about a DIY LRF using visible LED light and a Photoresistor, is something like this possible with a laser? Wouldn't that just be a simple range finder like the Sharp IR's? I want something more elaborate than that.

Then there's the ol' webcam/laser pointer setup (https://sites.google.com/site/todddanko/home/webcam_laser_ranger) but not really the route I want to go.

Also does anyone have any suggestions for machine vision via Kinect/Webcam/CMUcam etc?

 

Any help or suggestions would be greatly appreciated!

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**edit: found the CmuCam version i seemed to remember: http://hackedgadgets.com/2010/11/24/laser-range-finder-build/ **

I've been looking into doing this with computer (x86/x64/arm based robots) so i remembered a few links off of the top of my head:

I doubt this would work terribly well with a microcontroller but they may still help:

http://www.seattlerobotics.org/encoder/200110/vision.htm

http://www.sparkfun.com/news/490

https://sites.google.com/site/todddanko/home/webcam_laser_ranger (in the post already but still usefull i think; if only for the math involved...)

you might also look into Time Of Flight lasers or This one made for the rcx here: http://www.philohome.com/sensors/lasersensor.htm

I was also going to suggest the Lassiter but Gareth Beat me to it (his project so.. :P ). The basic principles aren't too complicated but you will need some decent calibration to get anything accurate i think.

That's awesome I haven't seen that build yet! Thanks for the info. Yea, I definitely have a lot to consider now and a few different routes! If you manage to get a LIDAR or similar setup with an x/86 etc based bot, let me know :)

Can Do. I'll write it up on LMR if i do manage to do that. I'm still looking at the kinect though.. Nice package with already done RGBD sensor. Would be kinda nice to start off using lasers though; one could theoretically build one around a class 1 ir laser and get something like a SICK laser scanner, etc. Seeing as The kinect has been reported to not work so well outdoors from what i've seen unfortunately (what with the sun swamping the IR based depth camera)...

I was looking at the Kinect too, but its relatively high price (even used / for parts on ebay) and its large size kind of throw me off. The SICK laser scanners look pretty, well.. sick lol. I can't seem to find a pricing for them however?

Being outdoors is another issue too! Ugh, so much to consider.

Btw I just remembered that Parallax has their own somewhat cheap laser rangefinder for $129.99 (http://www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/51/List/0/SortField/0/Level/a/ProductID/774/Default.aspx)

The Kinect Is nice for larger robots because it offloads the proccessing of the projected light to the kinect rather than the computer. It simply returns an RGB camera feed and a (grayscale?) Depth feed that can be relatively easily formatted. 

I forgot to mention the parallax sensor. Its about as expensive as the kinect though.. You can read the development blog though:

http://forums.parallax.com/showthread.php?126496-Joe-Grand-s-Laser-Range-Finder-A-Development-Diary

The sick Lasers are rather exspenive. A laser scanner like that; even a low end one easily costs 1,000+ USD... Mainly for industrial and University Research Projects. Not really geared towards the hobbyist. You can however see some usage of one as well as a kinect here:

http://www.pirobot.org/

It all depends on your budget and What exactly you are trying to do with the sensor. If you just want some distance data along a virtual ring around the robot you could design one similar to the one used over at pirobot or like the Neato Robotics Xv11's laser sensor. If you want full 3d the cheapest way to go is probably the kinect or possibly diy. It is possible to just use a camera and process data by isolating the returned laser/projected light from the rest of the feed and then using some trig on the location of those blobs or pixels from what i gather but that would have to be done on the robot's controller. I dont see much that has been done cheaply that does that sort of thing on its own and just passes distance data...

 

one more idea i found here (hack a laser range finding tool you might find in a hardware store):

 

http://www.sparkfun.com/news/726

I've used a few of the SICK laser products on work projects, and they are great but not cheap... probably around $1000 USD for the basic models. Industrial reliability does not come cheaply =)

I'm wondering if the Video Experimenter board for Arduino (http://nootropicdesign.com/ve/) would work alongside an attached laser like the aforementioned cam/laser project? Anyone have any thoughts or ideas about this? All I'd need is to attach a camera with an RCA cable to the shield...

I wonder if there would be some way to diffuse the laser beam to create line scanner and adapt fritzl's idea to read the reflected light? I'm still trying to refresh my memory when it comes to electronics and schematics, I dabbled in it when I was a wee boy.

ive seen lenses that make lines and various other patterns on ebay...